J.A. Brito et al. / Applied Catalysis A: General 398 (2011) 88–95
95
Fig. S6 in Supplementary Information), as previously observed for
dioxomolybdenum complexes containing hemi-labile ligands [24].
Relative to trans--methylstyrene epoxidation, monometallic
complexes 2 and 3 mainly led to the formation of the expec-
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the bis(oxazoline) ligand, 2 (entries 1 and 2, Table 5); less than
5% of benzaldehyde was observed in each case. Unfortunately,
no asymmetric induction was observed. However, the bimetallic
zaldehyde and benzylmethylketone instead of the corresponding
epoxide (entry 3, Table 5). Starting with trans--methylstyrene
epoxide in the presence of complex 1, benzaldehyde and benzyl-
methylketone were quantitatively obtained (Scheme 5); this result
points to that the epoxide is formed but it quickly decomposes
towards the formation of achiral by-products.
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In summary, bimetallic (1) and monometallic (2, 3) complexes
bearing chiral oxazoline ligands have led to active and chemoselec-
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exhibited by [MoO2Cl2(DME)] for the cyclooctene epoxidation
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